System for control of oil well production

ABSTRACT

A system for operating and controlling production of oil from a plurality of wells in which oil from the wells is passed to an oil and gas separator and a float switch mechanism is mounted in the oil and gas separator in which the float of the float switch contacts a normally-open microswitch, when it reaches its uppermost limit, which sends a signal to an alarm and also operates appropriate valves which shut off the flow of oil from the wells and pass oil from the oil-gas separator to an appropriate storage tank, a holding relay holds this particular signal until the float reaches its lowermost position, the float contacts a normally-closed microswitch, when it reaches its lowermost limit, which sends a signal which releases the alarm and control condition and the holding relay holds this signal until the float again reaches its upper position. The system may also be provided with an automatic counting system to count the total number of barrels produced from the entire group of producing wells during a particular day to thereby meet allowable limits for the field.

United States Patent [191 Nettles et a1.

11 3,7 5,442 [451 Oct. 16, 1973 SYSTEM FOR CONTROL OF OIL WELLPRODUCTION [76] Inventors: Henry D. Nettles, 1806 Swan'St.;

Bazzell, John S., 1604 W. Marshall Ave., both of Longview, Tex.

[22] Filed: May 22, 1969 [2]] Appl. No.: 826,848

[52] us. c|.....' 137/391, 137/412 Primary ExaminerRobert G. NilsonAttorney-Charles F. Steininger on.- GAS SEPARATOR TELEMETERNG CONTACTSCOUNTER [57] ABSTRACT A system for operating and controlling productionof oil from a plurality of wells in which oil from the wells is passedto an oil and gas separator and a float switch mechanism is mounted inthe oil and gas separator in which the float of the float switchcontacts a normallyopen microswitch; when it reaches its uppermostlimit, which sends a signal to an alarm and also operates appropriatevalves which shut off the flow of oil from the wells and pass oil fromthe oil-gas separator to an appropriate storage tank, a holding relayholds this particular signal until the float reaches its lowermostposition, the float contacts a normally-closed microswitch, when itreaches its lowermost limit, which sends a signal which releases thealarm and control condition and the holding relay holds this signaluntil the float again reaches its upper position. The system may also beprovided with an automatic counting system to count the total number ofbarrels produced from the entire group of producing wells during aparticular day to thereby meet allowable limits for the field.

4 Claims, 6 Drawing Figures A C SOURCE ","U NNDUCI 16 I973 SHEET 10F 3INVENTOR HENRY D. NETTLES M ATTORNEY PAHNTEDUBT 16 I973 SHEET 2 BF 3TELEMETERING I CONTACTS FIG.5

SiGNAL IIO V. AC

INVENTOR HENRY D. NETTLES ATTORNEY PATENTED UN 16 I975 SHEET 3 [IF 3 w mE q E 07 Cm Awo m M m m m m m M M UM R .l 6 R MT E 2 B m m 5% T J -l: wm H 5 6 8 OIL-GAS sEPARAToR\ DUMP VALVE BARREL IMPULSE METER STOCK TANKFIG. 6

. INVENTOR HENRY D. NETTLES BY Z :25

ATTORNEY SYSTEM FOR CONTROL OF OIL WELL PRODUCTION BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relates to thecontrol of oil production and in particular provides apparatus forachieving maximum permissible production from a group of wells inaccordance with arbitrarily assigned limitations on the rate of oilproduction.

2. The Prior Art In many oil-producing localities, conservation of oilpredetermined volume of production. Another object of the presentinvention is to provide an apparatus for changing a given condition ofoperation by means of a simple, yet effective float valve switch. Stillanother ob- 5 ject of the present invention is to provide an improvedreserves is now being practiced by assignment, either I tions, such aspressure, or the inclusion of dirt, sedi ment orother foreign matter inthe flow regulating surfaces of the choke or other mechanical flow.regulator cause changes in the rate of oil production from that to whichthe choke or other device is initially set. In operating a field ofwells, such departures from set flow rates can render it extremelydifficult to control the production from the field, such that dailyallowable production is not exceeded and yet such that total pro- Iduction is not substantially short of'the daily allowable for the field.As a consequence,there is a demand for a system of operating an oillease in which such departures from set flow rate are nullified and oilproduction up to the maximum allowable can be achieved without constantattention by an operator or operators.

It is therefore :desirable to automatically or at leastsemi-automatically operate the entire field thereby eliminating the needfor manual control. When automation equipment for the operation ofalease has been installed in the past, efforts have been made to' utilizeliquid level controllers in the oil and gas separators of the producingsystem in the same manner as these switches had previously been used formanual or open flow operation. However, these controllers experiencedconsiderable trouble when utilized with the automatic system. Themechanical dump valves on the s eparator were often changed tosnap-action dump valves and a combination of factors such as dump valvefailure, schedule of wells, pipe line pressure, etc., caused theincreased use of safety float switches. However, failures of the floatswitch caused the oil production to -be routed down the gas gatheringlines which resulted in a loss of oil production and a nuisance to thegasoline plant operation. Further, the float travel in existing floatswitches and the turbulence in the oil and gas separator caused theswitch to turn the motor valves located at the well site on and offnumerous times before final shut-down of the well and on numerousoccasions, these switches failed to shut in the lease. It was thereforeconcluded that a more reliable and better switch was necessary to obtainoptimum control. v

It is therefore an object of the present invention to provide 'anapparatus for effectively controlling oil well production from one or aplurality of wells to match a and highly effective float switchmechanism.

These and other objects and advantages of the present invention will beapparent from the following detailed description.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to anovel float switch mechanism in which the float mechanism operates afirst switch which, in turn, applies a signal to an external system andthis signal is held by a holding relay until the float mechanism reachesits maximum travel in the opposite direction at which time the floatoperates a second switch to transmit a second signal to theexternalsystem. The external system may be a system for controlling productionfrom one or more oil wells and in one extreme position, the float closesa valve in the oil-producing line while opening a valve from anaccumulating tank, while in the other extreme position, the

valve in the producing line is opened and the discharge valve is closed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 of the drawings shows in somedetail and partially in section the novel floatswitch of the present in-DETAILED DESCRIPTION OF THE INVENTION I In accordance with FIGS. 1 and 2of the drawings, a seamless bull plug 12 is threaded on its open end andadapted to fit into an appropriate female fitting in an oil and gasseparator, as hereinafter referred to. Float element 14 is mounted onrod 16. Rod I6 passes through the open end of bull plug 12 and isscrewed into one end ofa mounting shaft 18. Mounting shaft 18 passesthrough bushing 20 and into housing 22. Bushing 20 was threadablycoupled into bull plug 12 and housing 22. Bushing 20 also is providedwith weep hole 24. Mounted on the opposite end of shaft 18 is contactpin or arm 26. Contact pin 26 is held in shaft 18 by means of an Allenscrew 28. Mounted within housing 22 by means of screws 30 is mountingplate 32. A relay 34 is appropriately mounted on mounting plate 32 asare microswitches 36 and 38, respectively. Mounting plate 32 is providedwith adjustment slots 40 and 42, respectively, through whichmicroswitches 36 and 38 are mounted. By means of mounting throughadjusting slots 40 and 42, microswitches 36 and 38 may be moved towardorv away from contact pin 26 as desired. This adjustment may be made bymeans of nuts 44 which arepositioned on the mounting posts ofmicroswitch 36. Similar nuts are, of course, mounted on the mountingpost of microswitch 38 to permitadjustment of the position of thismicroswitch. Contact arm 26 contacts and operates operating buttons 45and 46 of microswitches 36 and 38, respectively.

FIG. 3 shows bushing 20 while FIG. 4 shows shaft 18 in some-detail.Shaft 18 is provided 'with appropriate annular grooves in which aremounted O-rings 48, 50 and 52. O-rings 48, 50 and 52, of course, preventfluid from passing from the oil and gas separator through bull plug 12to housing 22, which houses the electrical mechanism. Weep hole 24 inbushing 20 alsoaids in releasing any fluids which might get by O-rings48 and 50 before such fluids pass into the housing 22. Shaft 18 is heldin place in the float switch mechanism bymeans of lock ring 54.

FIG. shows the electrical system of the float switch. A l lO-volt ACsignal is supplied to the switch through lines 56 and 58. Line 56 hasmounted therein the coil 60 of holding relay 34. Also mounted in line 56is normally-closed microswitch 36. Mounted in line 58 is is productionstring 90, while leading from well 84 is production string 92. At thetop of production string 90 normally-open microswitch 385. Line 62 leadsto a sig nal or alarm, which is hereinafter discussed. Line 64 leads toan appropriate hydramotor of an operating valve which is also discussedhereinafter. Lines 66, 68 and 70 are provided for telemetering purposesbut are not utilized in the specific example discussed herein. Line 68and line 72 lead to the operating arms 74 and 76, respectively; of relay34. Relay 34 is a double-pole, double-throw relay. Contacts 78 and 80are associated with operating arms 74 and 76, respectively, of the reyThe operation of the float switch as described thus far is relativelysimple'as compared with the-previously discussed-prior art devices.Specifically, the float 14 travels approximately inches and such travelcan be varied by changing the length of the float arm, the size of thebull plug fitting or the spacing between the microswitches in the switchhousing. This large arc of travel of the present switch compares withthe travel of approximately 1 inch, which is a built-in disadvantage ofthe prior art switches. The float travel is transmitted to the controlmechanism by means of the O-ringsealed shaft and bushing arrangement.The control mechanism is designed with a holding relay 34 which holdsthe signal generated at the point of either high or low contact. Whenthe float risesto its highest point, it contacts the lower microswitch38 and operates both the alarm or signal and the control valve. Thesystem stays in this alarm and control position until the floatdropswith the fluid level to its lowest point and contacts the uppermicroswitch 36. Upper microswitch 36 releases the alarm condition andchanges the operating system back to normal operation. This signal isalso held until the float again travels to its uppermost position andagain contacts microswitch 38.

An appropriate relay for use in accordance with the present invention israted at 10 amps. and IIS volts AC, while appropriate microswitches havea 5 amp. rating at US volts AC. a

FIG. 6 of the drawings shows a system for automatically controlling oilwell production by use of the switch mechanism 10 of the presentinvention. In accordance with FIG. 6, wells or groups of wells 82 and 84are shown to be independently operable by means of the float switchmechanism together with timer mechanisms 86 and 88, respectively. Thewell or group of wells 82 or 84 may also be manually put on and takenoff stream,'thereby eliminating the timers. The

is choke valve 94 while choke valve 96 is positioned on productionstring 92. Choke valves 94 and 96 may be utilized to control the flowfrom wells 82 and 84 if less than the full potential of the well is tobe produced during a given operating period. Oil from well 82 passesthrough hydramotor valve'98, which is simply an electri'callycontrolled, fluid operated, piston valve for opening and closing a fluidline, while oil from well 84 passes through hydramotor valve 100.I-Iydramotor valve 98 is operated by anappropriate solenoid 102 whilehydramotor valve 100 is operated by solenoid 104. Fluids from eitherwell 82 or 84 pass into header 106. From header 106, the fluids pass tooil and gas separator 108. Mounted in the side of oil and gas separator108 is the bull plug-housing arrangement 12-22. Leading from thebullplug and into the interior of separator 108 is float 14. Oil and:gas separator 108, of course, separates gas from liquids and the gas isdischarged through line 110 while the liquid is discharged through line112. Oil discharged through line 112 passes through barrel ir'npulsemeter 114. Barrel imit may be completed automatic and automatically shutoff the entire system when the flow allowable has been produced. Counter122 can also be mechanical. Line 124 supplies power to the other ofswitch contacts 116. From an AC source of power not shown, power to thesystem is supplied through lines 126 and 128. Power is supplied to timer86 through lines 130 and to timer 88 through lines 132. Power from line128 passes to solenoid 102 through line 134, to solenoid 104 throughline timers may also be mechanical. Leading from well 82 I 136, to dumpvalve 138 through, its solenoid 140 by means of line 142, to alarm 144through line 146, and to the float switch mechanism through lines 56 and58. Oil after passing through impulse meter 114 is passed by dump valve138 into one or more stock tank units 148. Dump valve 138 may beoperated by gas from the gas space of separator 108 by contacting a linethrough a valve operated'by the float 14.

In the operation of the system in accordance with FIG. 6, either well 82or well 84 or groups of wells represented by these wells flows fluidthrough header 106 to oil and gas separator 108. When the float in oiland gas separator 108 reaches its upper limit, it, as previouslyindicated, closes normally-open switch 38. This, in turn, sends a signalto alarm 144 and to hydramotor valves 98 or and hydramotor valve 138.This signal closes the appropriate valve located at the well head andopens dump valve 138. As previously indicated, barrel impulse metercounts each barrel of oil discharged through dump valve 138 and recordsthis oncounter 122. The holding relay of the float switch system holds.the alarm and control condition until the level in oil and gas separator108. falls and float 14 reaches its lower limit. When the float reachesits lower limit, it contacts microswitch 36 opening this switch andthereby releasing the alarm and control condition. Valve 98 or 100 isopened to continue production and valve 138 is closed. This signal isalso held by the holding relay until oil and gas separator 108 againfills to the maximum limit and float 14 reaches its uppermost condition.

We claim:

1. A system for controlling the production of liquid from at least oneliquid producing well, comprising; producing flow line means leadingfrom said well to accumulator tank means; discharge flow line meansleading from said accumulator tank to at least one storage tank means;valve means mounted in said producing line means; valve means mounted insaid discharge line means; float means mounted in said accumulator tankmeans;- switch means operatively connected to said float means,including, a first switch operated by said float means when said floatis in a first of its two extreme positions; a second switch operated bysaid float when said float is in the second of its two extremepositions; electrical power means operatively connected to said firstvalve means and said second valve means through said switch means andholding relay means electrically connected to said first and said secondswitch means and adapted to hold the signal selected by each of saidfirst and second switches irrespective of the subsequent movement ofsaid float means until the other of said switches is operated by saidfloat means.

2. A system in accordance with claim 1 wherein the float means includesa rotatable arm adapted to be rotated by the float of said float meansand to operatively contact each of the switches of the switch means uponrotation thereof.

3. A system in accordance with claim 2 wherein the float of the floatmeans is located within the accumulator tank means, the electricalportion of the system is located outside the accumulator tank means, andthe rotatable arm passes through the wall of the accumulator tank means.

4. A system in accordance with claim 3 wherein the float means includesseal means mounted about the rotatable arm and adapted to provide afluid seal between the float of said float means and the electricalportion of the system.

1. A system for controlling the production of liquid from at least one liquid producing well, comprising; producing flow line means leading from said well to accumulator tank means; discharge flow line means leading from said accumulator tank to at least one storage tank means; valve means mounted in said producing line means; valve means mounted in said discharge liNe means; float means mounted in said accumulator tank means; switch means operatively connected to said float means, including, a first switch operated by said float means when said float is in a first of its two extreme positions; a second switch operated by said float when said float is in the second of its two extreme positions; electrical power means operatively connected to said first valve means and said second valve means through said switch means and holding relay means electrically connected to said first and said second switch means and adapted to hold the signal selected by each of said first and second switches irrespective of the subsequent movement of said float means until the other of said switches is operated by said float means.
 2. A system in accordance with claim 1 wherein the float means includes a rotatable arm adapted to be rotated by the float of said float means and to operatively contact each of the switches of the switch means upon rotation thereof.
 3. A system in accordance with claim 2 wherein the float of the float means is located within the accumulator tank means, the electrical portion of the system is located outside the accumulator tank means, and the rotatable arm passes through the wall of the accumulator tank means.
 4. A system in accordance with claim 3 wherein the float means includes seal means mounted about the rotatable arm and adapted to provide a fluid seal between the float of said float means and the electrical portion of the system. 